Short-lived noble gas effluent trends from a research reactor.

An understanding of anthropogenic sources of radioactive noble gases in the atmosphere is needed to enhance the discrimination ability of the International Monitoring System's sensors. These sources include commercial and research nuclear reactors and medical isotope production facilities. While abiding by local environmental ordinances these facilities all emit noble gas radioisotopes through normal operation. This research presents measurements and analysis of noble gas isotopes (41Ar, 135Xe, 135mXe, 137Xe, 138Xe, 87Kr, 88Kr, and 89Kr) made directly at the stack of the High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory. The Xe and Kr noble gases are concurrently observed with 41Ar, a neutron activation product, when the reactor is operational. The magnitude of the Xe and Kr noble gases released is not constant over the HFIR cycle, but they temporally match the 41Ar trend. An isotope activity ratio analysis of these shorter lived isotopes combined with the observation of the cycle's temporal trend helps understand the noble gas production mechanism at the HFIR. Isotopes with short half-lives are not useful for long-range environmental monitoring. However, these measurements could potentially be combined with atmospheric modeling to predict the background source term of the longer-lived Xe ratios at a monitoring station.

Device-related atypical pressure ulcer after cardiac surgery.

Medical devices must be closely monitored to prevent harm to patients. Pressure ulcers secondary to medical devices present a significant health burden in terms of length of stay in hospital and cost. Intensivists, anaesthetists and other professionals involved in managing critically ill patients following cardiac surgery need to be aware that pressure ulcers may develop in atypical sites and present at a later stage of the hospital stay. This case report highlights the important issue of device-related pressure ulcers in the cardiac surgical intensive care setting, particularly when the clinical status of the patient may preclude routine assessment and prophylaxis. An algorithm for preventing such pressure ulcers is suggested.